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County file — CA

Underground Storage Tanks in Mariposa County, CA — 37 facilities, 98 leak records

What the EPA UST Finder snapshot (2018–2021 state data) shows for Mariposa County, population 18,014.

37UST facilities
71tanks in service
0closed tanks
98leak records
6open cases
92no further action

Mariposa County has 37 registered underground storage tank facilities in the national snapshot — gas stations, fleet yards, and other regulated fuel sites — holding 71 tanks in service and 0 tanks that have been closed or removed. Over the life of the program, 98 fuel releases were reported here; 92 (94% of records) were investigated and closed with No Further Action, and 6 of those cleanup cases were still open when the snapshot was compiled.

That works out to 39.4 tanks in service per 10,000 residents, well above the California average of 9.5 per 10,000. Countywide numbers are context, not a verdict on any parcel — tank risk is hyper-local, falling off within a few hundred feet.

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Frequently asked questions

How many underground storage tanks are in Mariposa County, CA?

The EPA UST Finder snapshot lists 37 registered UST facilities in Mariposa County with 71 tanks currently in service, 0 closed or removed tanks, and 0 temporarily out of service.

How many fuel leaks have been reported in Mariposa County?

98 releases from underground storage tanks are on record for Mariposa County. 92 (94%) reached No Further Action status, while 6 cleanup cases remained open in the snapshot.

How do I check a specific address in Mariposa County?

Use the free TankCheck screening at https://tankcheckusa.site/ — paste any Mariposa County address to map every registered tank and reported leak within a mile, with distances in feet and an A–F screening grade. Verify current records with the California SWRCB UST Program.

Verify with the state

The live regulatory record for any Mariposa County facility or leak case is held by the California SWRCB UST Program. Newer records than this 2018–2021 snapshot may exist.

Nearby countys in California

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